Metal concentrations in sediment, water and clams from the Indian River Lagoon, Florida

A survey of trace metal concentrations in sediment, water and the hard clam (Mercenaria mercenaria) was carried out in the Indian river lagoon, Florida, U.S.A., in 1992. Forty-three locations were sampled for sediments and water. Clams were found and collected at 22 of these locations. Sediment metal concentrations were strongly affected by proximity to freshwater tributaries and by the bathymetry of the Indian river lagoon. Arsenic, cobalt, nickel and vanadium concentrations were correlated with sediment aluminium concentrations. Dissolved metal concentrations were highly variable. Concentrations of dissolved copper and lead varied directly with zinc. Concentrations of metals in the clam were generally less variable than those found in sediment and water samples. No significant correlations were observed between metal concentrations in the clam and those in sediment or water. In the clam tissues, concentrations of lead, manganese and zinc were correlated with iron.